Airbnb just checked in its 500 millionth guest

For $181 per night, Airbnb guests can stay in a castle in Galway, Ireland.

Many have taken the home-sharing business up on this offer with the company sharing today the castle supplies its most-booked private room. Along with that fun datapoint, Airbnb shared a slew of other stats indicating an upward trajectory for the 12-year-old company.

Most notably, Airbnb has just recorded its 500 millionth guest arrival across one of its 6 million homes, yurts, tree houses, boats and more.

Airbnb crossing the half-billion mark isn’t surprising given recent aggressive expansion strategies. Valued at $31 billion, the San Francisco-headquartered business recently announced it would acquire HotelTonight in a deal reported to be worth roughly $465 million.

Airbnb’s long-term goal is to build an end-to-end travel platform complete with home sharing, hotel booking, business travel arrangements, experiences and more. Folding in HotelTonight, a mobile app that lets travelers arrange last-minute accommodations, accelerates its path toward owning the peer-to-peer rental market and more. Already amongst the most acquisitive unicorns, per Crunchbase News, Airbnb is also in said to be considering purchasing a stake in Oyo, an Indian hotel startup.

According to the analytics platform Second Measure, Airbnb is rapidly surpassing hospitality incumbents. Since 2016, Airbnb has tripled sales, while larger hotel chains have observed sales growth of just 11 percent. Airbnb’s annual sales have overtaken IHG and Hilton, and are well on their way to exceeding Marriott, which has dominated the industry since acquiring Starwood Hotels in 2016.

All of this bodes well for Airbnb, which is said to be considering a 2019 or 2020 initial public offering. The company has to date raised $4.4 billion in a combination of debt and equity funding from venture capital investors including Andreessen Horowitz and Sequoia Capital. In January, Airbnb said it was profitable for the second consecutive year on an EBITDA (earnings before interest, taxes, depreciation and amortization) basis.

In addition to the 500 million milestone, Airbnb has shared that its hosts have earned $65 billion from renting out space on the platform. That number is expected to swell, quick, as Airbnb says it saw 152 percent growth in the number of rooms available on its platform. The geographic distribution of guests has expanded, too, with outlying markets increasing their share of arrivals.

Finally, the age of hosts has become more diverse. Seniors are now the fastest-growing demographic in the U.S. while 70 percent of bookings in the last three years were made by guests under the age of 40. Millennials around the world have spent over $31 billion booking travel on Airbnb.

Airbnb currently dominates the peer-to-peer rental industry, but with Expedia gaining market share via its subsidiary HomeAway and Bookings Holdings doing its best to compete through Bookings.com, Kayak and Priceline, Airbnb may not be able to sustain this growth rate.